Break the stems off of the peppers; split them and remove the seeds (unless you really like it hot ). Toss the peppers in a sauce pan with about 4 cups of water and let them simmer for a while. In the meantime, take the meat, onions and garlic and a sharp knife and sit down to a cutting board. Cut the meat into bite-sized pieces, removing most of the fat . Next, coarsely chop the three large onions. Finally, mince the cloves of garlic.
Toss the meat into a large stock pot with a couple of tablespoons of oil. While it is browning, toss in ground cumin to taste. When the meat is mostly browned, throw in the onions and the garlic. Stir periodically until the onions are wilted and translucent. Add the crushed tomatoes and turn the heat down.
By this time the peppers should be ready. You might want to let them cool a little depending on how you do the next few steps.
I take the peppers from the water with a slotted spoon and liquefy them in our food processor. I'll add some of the water to get a slurry the consistency of tomato sauce. Then, to remove the seeds and little bits of pepper skin I run the slurry through a food mill. You could just go straight to the food mill and save the step of dirtying the food processor. Whatever you decide, you should end up with a couple of cups of a heavy, dark red, pungent sauce. Add the sauce to the meat.
You can put the beans in any time you want, but remember: they sink to the bottom of the pan and could burn there or overcook into an unpalatable mush. I usually hold them aside until about an hour before I plan to serve.
Note: The red water left over from the peppers is used to replenish any water lost as the meat, onions, and sauce cook over the course of the day. I usually just throw it all in, anyway.